| 摘要 |
619,571. Sewing-machines. SINGER MANUFACTURING CO. Dec. 12, 1946, No. 36779. Convention date, Aug. 9. [Class 112] A thread tension device comprises a hollow support 32, a biassing spring 51 and a sliding bias compressing nut 49 both housed within the support, tension discs 42, 43 located entirely in front of the spring and carried externally on the support, and an adjusting screw 73 partly within the support. A plate 31, fixed to the support, has oppositely disposed thread-guide and check-spring-stop lugs, and is adjustably secured to the machine head 12 by a screw and slot. One end of the check-spring 58 enters a hole in a sleeve 52, attached to the support by a set screw 56, and the other end 61 surrounds a reduced part 44 of the support. A pin 81 on the screw 73 engages one of a series of holes in a conical washer 69, provided with a thread tension scale and a lug 71 to engage a stop on a guard-plate 62. The guard plate has also an index mark for the scale, three lugs 67 engaging the disc 43, and a thread guide hook. A V-shaped lever pivoted in the machine head has one arm moved by the presser bar lifter, and the other provided with an outer boss carrying a return spring and an inner boss engaging the threaded end, of the screw 73 to release the thread tension of the presser bar is raised. |
